http://blog.chinaunix.net/uid-24426415-id-77492.html
1、
for uppercase in `ls`
do
for lowercase in `ls $uppercase|tr [A-Z] [a-z]`
do
mv $uppercase $lowercase 2>/dev/null
done
done
2、
typeset -u Lcase
for Ucase in `ls`
do
Lcase=$Ucase
mv $Ucase $Lcase
done